Well, here's how to install Hangouts without waiting for Google to release the updates that make it work.
Start adb as root (adb root)
Mount system as writeable (adb remount)
(If it fails, kill adb server and start it again (adb kill-server && adb server start)
As root, go to system/app (cd system/app)
Delete Talk.apk (rm Talk.apk or mv Talk.apk /sdcard/Talk.apk)
Now, go to play store on your phone, and search for Hangouts.
You can install it now!! :D